Returns a keyword denoting where object is
stored. The possible return values are:

:immediate, which means the object is not
referenced with a pointer (fixnums, e.g.)

:static, which means the object is stored in an
area which is not garbage collected.

:tenured, which means the object is stored in
oldspace (also called tenured space).

:new,
which means the object is stored in newspace but will, if it survives,
eventually be tenured.

:pan, which means that the object is stored in
newspace and will never be tenured. (The name comes from Peter Pan,
who never grew old.) See the note just below. (Note that lispval-storage-type returns the
keyword :panified rather than
:pan.)

Note on :pan objects: Only system-created objects can have
storage type :pan but sometimes these objects are
created as a consequnce of user action. The key vector of a weak-keys
hashtable is typically a :pan object, though this
can be controlled. See cl:make-hash-table in
implementation.htm.